Field of the Invention
The present invention relates to sleep apnea devices and particularly to the type inserted in the nasal passages to control exhaling by the patient.
Description of the Related Art
Apnea is a Greek term meaning “without breath”. Simply stated apnea means cessation to breathing, something that may lead to decreased oxygen saturation (hypoxia) and an accumulation of carbon dioxide in the bloodstream. Hundreds of millions of patients are afflicted with sleep apnea, a dangerous condition which can lead to sleep deprivation and the consequent unhealthy existence and even death.
There are three types of sleep apnea: Obstructive, Central and mixed. Obstructive sleep apnea is the more common of the two. Obstructive Sleep Apnea can occur as repetitive episodes of complete or partial upper airway blockage during sleep. During an apnea episode, the diaphragm and chest muscles work harder as the pressure increases to open the airway. Breathing frequently resumes with a loud gasp or body jerk. These episodes can interfere with sound sleep, reduce the flow of oxygen to vital organs, and cause heart rhythm irregularities.
In Central Sleep Apnea, the airway is not blocked but the brain fails to signal the muscles to read due to instability in the respiratory center. This affliction is not addressed by the present invention.
Mixed sleep apnea is combination of both obstructive and central.
While Obstructive Sleep Apnea (OSA) is commonly associated with obesity and the male gender, it affects a broad cross section of the population. Other risk factors include habitual snoring, which is often a precursor of more serious upper respiratory disorders such as Obstructive Sleep Apnea. In fact, results from a recent study indicate that 1 in 3 men and 1 in 5 women who snore habitually suffer from some degree of Obstructive Sleep Apnea.
Symptoms of OSA may be recognized by the bed partner or the patient him or herself. The most common symptoms include snoring, daytime sleepiness or fatigue, restlessness during sleep, sudden awakening with a sensation of gasping or choking, dry mouth or sore throat upon awakening, intellectual impairment, such as trouble concentrating, forgetfulness or irritability, night sweats, sexual dysfunction and headaches.
Left untreated sleep apnea can result in a number of health problems including hypertension, stroke, arrhythmias, cardiomyopathy (enlargement of the muscle tissue of the heart), congenital heart failure, diabetes, and heart attacks. In addition, the untreated sleep apnea may be responsible for job impairment, work related accidents, and motor vehicle crashes as well as academic underachievement in children and adolescents. The risks are significantly increased for those suffering from obesity, chronic lung disease, cardiac disease or COPD.
Obstructive Sleep Apnea Syndrome (OSAS) is a debilitating sleep and breathing disorder which can lead to numerous different afflictions sometimes resulting in stroke, heart attack or other ailments. Debilitating sleep and breathing disorder has been defined as the cessation of breathing for 10 seconds or more (an apnea) at least five times per hour of sleep. Apnea Hypopnea Index (AHI) is the average number of apnea intervals per hour. An AHI of 5 is considered very minimal, less than 15, mild, 30, moderate and over 30, severe.
It is known that the body and muscles relax which can cause excess tissue to collapse into the upper airway (back of the mouth, nose and throat) and block breathing. When breathing is interrupted by an obstruction in the airway, the body reacts by waking enough to start breathing again. These arousals may occur hundreds of times each night but do not fully awaken the patient, who remains unaware of the loud snoring, choking and gasping for air that are typically associated with Obstructive Sleep Apnea Syndrome. Obstructive Sleep Apnea sufferers never get “a good night of sleep” because repeated apneas and arousals deprive patients of REM and deep-stage sleep leading to chronic daytime exhaustion and long-term cardiovascular stress.
Obstructive Sleep Apnea has a profound impact on an individual's health. Excessive daytime sleepiness caused by disruption of normal sleep patterns leads to a significant increase in the rate of accidents for afflicted patients, including a seven fold increase in automobile accidents. Over the long term, Obstructive Sleep Apnea is associated with greater risk of hypertension and cardiovascular disease. The National Commission on Sleep Disorders Research estimates that 3800 cardiovascular deaths due to sleep apnea occur each year. In addition, loud snoring and intermittent breathing interruptions can affect the quality of sleep of the Obstructive Sleep Apnea patient's bed partner. Witnessing an apnea can be a frightening experience because the Obstructive Sleep Apnea patient appears to be suffocating.
According to published data, 24% of adult men and 9% of adult women, or more than 20 million Americans, are estimated to have some degree of Obstructive Sleep Apnea. Of these, six million are estimated to have cases severe enough to warrant immediate therapeutic intervention. However, Obstructive Sleep Apnea was not well understood or recognized by physicians until recently and only a fraction of these 20 million Obstructive Sleep Apnea patients have been diagnosed and treated by a physician. The number of patients currently undergoing treatment is probably on the order of one million.
Hypertension refers to elevated blood pressure and is a common disease, characterized by elevated systolic and/or diastolic blood pressure. Despite the prevalence of hypertension and its associated complications, control of the disease is somewhat inadequate. Only a third of the population suffering with hypertension control their blood pressure adequately. OSA, left untreated can lead to hypertension.
It is known that various forms of positive airway pressure during sleep can provide an effective form of therapy for apnea sufferers. Approaches taken have been to apply Continuous Positive Airway Pressure (CPAP) in which a positive pressure is maintained in the airway throughout the respiratory cycle or Bi Level Positive Airway Pressure (BiPAP) in which positive pressure is maintained during inspiration but reduced during expiration. Intermittent mechanical positive pressure ventilation can be provided where pressure is applied when an episode of apnea is sensed. Positive airway pressure devices have traditionally employed either a face mask to cover the patient's nose or nasal pillows as the interface between a ventilation device and the patient's airways. These interfaces suffer the shortcoming that they are sometimes cumbersome and uncomfortable to wear, often leading to rejection by the patient.
The face mask typically requires a harness, headband or other headgear to hold the mask in position, something patients frequently find uncomfortable, particularly when sleeping. Such face masks are constructed to seal against the patient's face and sometimes chafe against the patient's skin which may cause facial sores, particularly if the patient's sleep pattern involves movement and repositioning during the night. Further, the seal against the patient's face may leak thus reducing or eliminating the efficacy of the device.
Some face mask designs are intended to apply pressure to the sinus areas of the face adjacent the nose, causing the airways to narrow, thereby increasing the velocity of flow through the airway, but decreasing the pressure against the nasal mucosal walls. This process tends to strip moisture from the mucosal wall during inspiration thus drying the wall and producing a burning sensation. Consequently, many patients find the face mask uncomfortable, somewhat ineffective and often results in the patient discontinuing that therapy.
Examples of nasal masks are shown in U.S. Pat. Nos. 5,335,654 and 5,535,739 to Rapoport which describes a CPAP system using a conventional nasal mask.
It has also been proposed to provide nasal pillows which are pressed against the interior portion of the nares to close the nostril openings. Nasal pillows require a robust headband or harness to maintain the pressure thus often leading to discomfort similar to that suffered by use of the face masks.
U.S. Pat. No. 4,782,832 to Trimble discloses nasal pillows held in a patient's nose by a harness arrangement and incorporating two accordion or bellows shaped nipples for fitting against the nostril openings.
It has been recognized that nasal Expiratory Positive Airway Pressure (EPAP) may tend to maintain the patient's airways open during sleep to treat apnea conditions. Different devices have been proposed in effort to provide EPAP, including elongated adhesive strips mounting in the central area a one way valve intended to be placed over the nostrils when retiring. The device is intended to allow the valve to open as a patient inhales but as the patient exhales, close the valve to create a back pressure in hopes of opening the airways to relieve snoring. Such devices, while appearing to offer relief in theory, suffer the shortcoming that the single valve is ineffective to properly control flow through both the patient's nostrils and testing shows that the adhesive strip is challenging to apply and maintain in position during the sleep period.
CPAP is the preferred initial treatment for most people with Obstructive Sleep Apnea. With CPAP, patients wear a mask over the nose and/or mouth. An air-blower forces air into a mask and through the nose and/or mouth. The pressure is adjusted so that it is just enough to prevent the upper airway tissues from collapsing during sleep. The pressure is constant and continuous. CPAP prevents airway closure in use, but apnea episodes return when CPAP is stopped or is used improperly. Patients typically find such masks cumbersome, bulky, uncomfortable, noisy and in need of daily cleaning thus discouraging continuous use.
Other devices have been proposed such as mandibular appliances for patients with mild sleep apnea, dental appliances that prevent the tongue from blocking the throat and/or advance the lower jaw forward. These devices help keep the airway open during sleep.
In effort to avoid the discomfort of CPAP masks, it has also been proposed to provide individual nasal adhesive patches with individual one way valves to be adhered to the patient's nostrils to generate a back pressure upon exhaling. Such devices, while promising in theory, are not adequately affixed to the nostrils in such a manner such as to provide positive lodging in the nasal passage and to positively block flow upon exhaling.
Other efforts to avoid the dreaded CPAP machine proposes an exterior adhesive strip to be applied transversely across the patient's nose and configured with a spring like band to purportedly hold open and extend the nasal passages. Such devices fail to effectively address the issues of sleep apnea.
Chronic Obstructive Pulmonary Disease (COPD) includes chronic bronchitis, emphysema and asthma. In both chronic bronchitis and emphysema, air flow obstruction limits the patient's airflow during exhalation. COPD is a progressive disease characterized by a worsening base line respiratory status over the period of many years with sporadic exacerbations often requiring hospitalization. Early symptoms include increased sputum production and sporadic acute exacerbations characterized by increased cough, purulent sputum, wheezing and fever. Late in the course of the disease, the patient may develop hypercapnia, hypoxemia, cor pulmonale with right-sided heart failure and edema.
Pulmonary rehabilitation is frequently used to treat patients suffering from a variety of medical ailments such as those mentioned. For example, COPD patients are taught new breathing techniques that reduce hyperinflation of the lungs and relive expiratory airflow obstructions. Typically, these new breathing techniques include diaphragmatic and pursed-lip breathing. Pursed-lip breathing involves inhaling slowly through the nose and exhaling through pursed-lips (as if one were whistling), taking two or three times as long to exhale as to inhale. Most COPD patients instinctively learn how to perform pursed-lip breathing in order to relieve their dyspnea. It is believed that producing a proximal obstruction (e.g. pursing the lips) splits open the distal airways that have lost their tethering in certain diseased states.
It has been reported that pursed-lip breathing by COPD patients results in a reduction in respiratory rate and an increase in tidal volumes and an improvement of oxygen saturation. However, pursed-lip breathing requires conscious effort, thus the patient cannot breathe through the pursed lips while sleeping. As a result, the patient can still become hypoxic at night and may develop pulmonary hypertension and other sequelae as a result.
Non-invasive Positive Pressure Ventilation (NPPV) is another method of treating diseases that benefit from regulation of the patient's respiration. NPPV refers to ventilation delivered by a mask, nasal prongs, pillows or face mask. NPPV eliminates the need for intubation or tracheostomy.
NPPV can deliver a set pressure during each respiratory cycle, with the possibility of additional inspiratory pressure support in the case of bi-level devices. It is recognized that most patients experience difficulty adapting to nocturnal NPPV leading to poor compliance. Mask discomfort is a very common problem for patients new to NPPV, because the high pressure om the nose, mouth and face and because the tight straps are uncomfortable.
Both the pursed-lip breathing and the use of NPPV have been shown to offer significant clinical benefits to patients with a variety of medical illnesses including COPD, heart failure, pulmonary edema, sleep apnea and other sleep breathing disorders. Expiratory resistance is believed to provide the bulk of clinical improvements when using pursed-lip breathing and NPPV, through a variety of physiological mechanisms. For example, in COPD expiratory resistance is believed to facilitate expiration, increase tidal volume and decreases respiratory rate. Various devices have been proposed for applying positive pressure to the patient's nostrils and even for balancing flow between the two nostrils. See U.S. Pat. No. 5,740,799 to Nielsen.
It has been proposed to extend the expiratory time in effort to reduce the respiratory rate as by incorporating a flap valve in a nasal device for restricting exhalation flow and facilitating connection to an oxygen source. A device of this type is shown in U.S. Pat. No. 7,856,979 to Doshi. While proposing a degree of restriction during exhalation, Doshi fails to show a device and method of use to fully block exhalation so that a patient might benefit from his or her own biological responses to self-regulate during the inspiration/expiration cycle.
Furthermore, Doshi teaches a relatively undefined construction for his so-called airflow resistor and adopts the rather traditional approach of incorporating face mask straps, hold-fasts or the like necessary to hold the resistor in position. There have been many efforts in the art to provide a nasal device which closely fits the nasal passages to seal around the nares and which are comfortable for the wearer. Experience has proven that even with securement straps, the nasal devices often dislodge from the nares. It is recognized that it is beneficial and therapeutic to supply a sufficient air flow rate of respiratory air to achieve a minimum level of air volume in the lungs. If the air volume in the lungs falls below the minimum level the lungs may collapse which may be extremely dangerous or even deadly to a patient. Moreover, the back pressure can increase oxygen levels in the lungs and decrease carbon dioxide levels. This will also improve Ph by removal of carbon dioxide which is an acid, from the blood.
Many different configurations of CPAP devices have been proposed, including face mask, nasal prongs and nasal cannulas, each having advantages and disadvantages. One objective of the art has been to devise a comfortable nasal cannula which is economical to manufacture and practical to use. Prior art nasal cannulas have been disclosed in many forms with various methods of securing the device to the nasal passageway. One such cannula assembly is disclosed in U.S. Pat. No. 3,513,844 utilizing an adjustable strap to encircle the individual's head. A similar device is disclosed in U.S. Pat. No. 4,106,505 wherein the supply tubes to the cannula are hooked over an individual's ears and around the head, Even more cumbersome is the device disclosed in U.S. Pat. No. 5,477,852 incorporating a headband for holding and positioning the nasal inserts and associated supply tubes. Yet another system in U.S. Pat. No. 5,271,391 discloses a cannula which is secured by applying strips of pressure sensitive adhesive tape to the supply tubes leading from each side of the cannula, thereby attaching the supply tubes to the cheeks of an individual with a cannula positioned in between. These head harness devices are commonly found necessary to hold the CPAP prongs in place.
Other efforts have led to a proposal of CPAP devices for treatment of sleep apnea with relatively stiff or rigid nasal cannula surrounded by inflatable cuffs to retain the cannula in the pares as shown in U.S. Pat. Nos. 5,269,296; 5,477,852 and 5,687,715 to Landis. It has also been proposed to telescope a soft ring-shaped flange over a cannula as shown in U.S. Patent Publication No. 2009/0032208 to Bare to assist in retaining the cannula in the patient's mask.
However, these prior methods, are in some cases, rather complicated and expensive to manufacture and in the other cases, ineffective to secure the cannula in place without cumbersome head gear. Some apply pressure to an individual's nose and upper lip thereby causing pressure necrosis in the upper center of the nose. Many of the head harnesses fail to adequately secure the prongs in position, particularly with infants or patients who tend to roll around or move during the sleep phase. The discomfort of head harnesses and the like can often lead to the patient intentionally or unintentionally removing the harness and disconnecting the device thereby leading to sleep apnea, distractions, bradycardia, or hypoxia which is known as a dangerously low oxygen level in the blood. In practice, the tubing for many of these head harness devices is typically draped around both sides of the patient's cheek which means that the most comfortable lying position is on the patient's back thus producing a tendency to snore and create a uncomfortable sleeping position for the patient.
Other efforts to develop satisfactory anchoring systems include adhesive devices which attach directly to the nose. U.S. Pat. No. 4,823,789 discloses a nose tube anchoring strip which has an adhesive coated strip to fit over the individual's nose and an appendage for holding a nasal-gastric tube in place. A similar device is found in U.S. Pat. No. 5,156,641 disclosing an anchoring cord adhesively attached to an individual's nose at one end and attached to hold the naso-gastric catheter at the other end. U.S. Pat. No. 5,138,635 shows an anchoring device with a body engagement portion which adheres across the nose of an individual with cannula engaging portions extending downwardly.
One of the challenges facing artisans in seeking to develop a satisfactory apnea device is, to provide a device which affords adequate air flow while avoiding the necessity of applying uncomfortable head harnesses, masks and the like to hold the device in place within the nasal passages. A particular problem is the discomfort associated with the use of such devices. That is, the artisan is faced with the dilemma that a nasal device must be of sufficient structural integrity to maintain a flow passage sufficiently opened as to afford a high rate of flow during an expiration while, at the same time, providing comfort within the nasal passage. As will be recognized abrupt changes in cross sectional shape of the cannula device, as such as presented by the end of a rigid wall will, over time, create irritation within the soft tissues of the nasal passage thereby discouraging continuous use and even resulting in an unconscious desire by the patient to involuntarily remove the device during the sleep period. Until now the artisan has been faced with the dilemma of sacrificing rigidity in the cannula to achieve comfort of seeking to devise a cannula with varying rigidity.
This issue of discomfort in the nasal passages has plagued the art for some time. Numerous different approaches have been taken in effort to solve the dilemma of anchoring the nasal devices in place in a manner which will not excessively contribute to the patient's discomfort while providing a robust flow passage.
As an example, U.S. Pat. No. 4,823,789 discloses an adhesive device to attach directly to the nose via an adhesive coated sheet including an appendage for holding the naso-gastric tube. In this regard, it has been proposed to provide sponge-like nasal tips which are manually compressible to reduce the size for convenience of insertion and having a relatively slow rate of expansion seeking to block the nasal passage. A device of this type is shown in U.S. Pat. No. 4,648,398 to Agdenowski. Devices of this type, while having a sealing capability are relatively cumbersome and fail to address the issue of high rates of flow in the flow passage.
Other efforts have led to the proposal that a nasal buff be provided with external nasal sealing means which incorporate pliable, conical nare pillows to be constructed of rigid, synthetic resin material and include a bellows arrangement for accommodating the various orientations of the nasal passage or a nasal pillow constructed of a soft resin such as cell foam or gel filled with silicone. Such devices, while providing some comfort in accessing the orifici at the distal extremity of the nasal passages, fail to address the complications relating to high flow rate and convenient retention in the nasal passages without complicated tubing and headgear.
Other proposals have been made for a tubing system to surround the user's head or neck and carrying a crescent shaped tube device in the frontal area with upwardly projecting tubes for telescopically receiving tubular nasal elements formed at their proximal extremities with enlarged rims. A device of this type is shown in U.S. Pat. No. 6,478,026 to Wood. Such devices incorporate relatively complicated valve systems and, furthermore, are cumbersome to use and can readily generate discomfort in the nasal passages due to the misalignment between the orientation of the patient's nasal passages and the device itself.
It has also been proposed in the unrelated art of medicine that inhalers incorporate a nasal interface tube with left and right nasal prongs that pinch the nasal septum in order to retain the device in place. A device of this type is shown in U.S. Patent Application Publication No. 2002/0046751.
In recognition of shortcomings of the interface with the patient's nostrils and sealing capabilities, it has been proposed to provide a harness mounting nasal tubes at the interface with various fittings which abut or only slightly penetrate the nasal passage. A device of this type is shown in U.S. Pat. No. 8,136,527 to Wondka. These devices are also relatively cumbersome in that the harness typically involves a connection about the patient's ears or around his or her neck and little attention is given to the sealing characteristics of the peripheral of the nasal devices with the nasal tissues or any consideration to possible discomfort deep in the nasal passages.
Other devices have been proposed for releasing oxygen only during inhalation. A device of this type is shown in U.S. Pat. No. 8,365,736 also to Doshi.
Other devices, such as ball valves have been proposed in unrelated art for interrupting oxygen supply during the patient's exhale phase. A device of this type is shown in U.S. Patent Application Publication No. 2008/0142012 to Farnsworth.
It has been recognized that debris can build up in a valve arrangement of a face mask and that the consequent pressure build up can be relieved through a side vent of a control valve and an anti-asphyxia bypass feature. A device of this type is shown in U.S. Pat. No. 7,559,326 to Smith. Devices of this type, while tending to serve their intended purpose, suffer the shortcoming that some patients resist use of a mask covering a portion of the patient's face and the fact that failure to totally block exhalation fails to afford effective relief from a patient suffering from sleep apnea.
Also, in unrelated art, relatively large diameter tracheotomy valves have been proposed which include diaphragms spaced some distance from the end of the valve body for opening when a negative pressure has been applied. A device of this type is shown in U.S. Pat. No. 8,051,853 to Bare. To Applicant's knowledge, such devices have not been incorporated in sleep apnea nasal devices or sized or configured in such a way as to be so incorporated.
It is believed that at least some forms of sleep apnea may be treated by fully and completely blocking the patient's exhalation while allowing for free inhaling at a relatively high flow rate. While it has been proposed to restrict flow during the exhaling phase as in U.S. Patent Publication No. 2013/0081673, such devices and their methods of use do not provide the benefits of complete blockage.
There thus remains a need for a device of this type which is convenient for a patient to apply but which will effectively and fully block the patient's exhalation without otherwise interfering with breathing.